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Orthopaedic Surgery Jun 2021Measure and systematically evaluate the distribution of microhardness in the human skeleton.
OBJECTIVES
Measure and systematically evaluate the distribution of microhardness in the human skeleton.
METHODS
Three fresh corpses were obtained, aged 62 (male), 45 (female), and 58 years (male). Soft tissues were removed, and all axial and unilateral appendicular bones were freshly harvested. All three skeletons were examined by X-ray and computed tomography (CT) to exclude skeletal pathology. Only bones from donors with no known skeletal pathology were included in the study. Axial and unilateral appendicular skeleton bones from each of the three donors were obtained, except for ear ossicles, hyoid bone, tailbone, and 14 phalanges of the foot, for which samples were difficult to obtain. Precision bone specimens with a thickness of 3 mm, which were cut with a Buehler IsoMet 11-1280-250 low-speed diamond saw (Buehler, USA), were obtained from all important anatomic sites in a direction perpendicular to the mechanical axis of each bone. Micro-indentation (the Vickers hardness test) was performed on the surface of each specimen using a microhardness tester with a diamond indenter. Hardness value (HV) was computed for each indentation. Each bone specimen was divided into several regions of interest. Indentations were carefully made and computed. Then we analyzed the data to identify hardness distribution rules at different anatomic sites.
RESULTS
In total, 5360 indentations were made in 1072 regions of interest in each donor. Hardness of the axial and appendicular bones were all inhomogeneous depending on the anatomic sites, but the distribution of microhardness followed certain rules. The mean hardness value ranged from 24.46 HV (HV = hardness value, kgf/mm ) for the sacrum to 53.20 HV for the shaft of the tibia. The diaphysis was harder than the metaphysis, and the proximal and distal epiphysis had lower values (8.85%- 40.39%) than the diaphysis. Among the long bone diaphyses, the tibia cortical bone (51.20 HV) was the hardest, harder than the humerus (47.25 HV), the ulna (43.26 HV), the radius (42.54 HV), and the femur (47.53 HV). However, in some anatomic sites such as the lumbar vertebra (cortical bone 32.86 HV, cancellous bone 31.25 HV), the cortical shells were sometimes not harder than the internal cancellous bones. The lumbar vertebra (32.86 HV) was harder than the cervical vertebra (28.51 HV) and the thoracic vertebra (29.01 HV).
CONCLUSIONS
The distribution of microhardness in the human skeleton follows certain rules. These distribution rules could be used to predict the mechanical properties of bone and progress in this field could provide data for the basis of a new three-dimensional printing technique, which may lead to new perspectives for custom-made implants.
Topics: Biomechanical Phenomena; Bone and Bones; Cadaver; Female; Hardness; Humans; Male; Middle Aged
PubMed: 33973714
DOI: 10.1111/os.12841 -
The Canadian Veterinary Journal = La... Dec 2020
Topics: Animals; Atlanto-Axial Joint; Cervical Vertebrae
PubMed: 33299238
DOI: No ID Found -
PloS One 2022Different hip pathologies can cause geometric variation of the acetabulum and femoral head. These variations have been considered as an underlying mechanism that affects...
Different hip pathologies can cause geometric variation of the acetabulum and femoral head. These variations have been considered as an underlying mechanism that affects the tribology of the natural hip joint and changes the stress distribution on the articular surface, potentially leading to joint degradation. To improve understanding of the damage mechanisms and abnormal mechanics of the hip joint, a reliable in-vitro methodology that represents the in vivo mechanical environment is needed where the position of the joint, the congruency of the bones and the loading and motion conditions are clinically relevant and can be modified in a controlled environment. An in vitro simulation methodology was developed and used to assess the effect of loading on a natural hip joint. Porcine hips were dissected and mounted in a single station hip simulator and tested under different loading scenarios. The loading and motion cycle consisted of a simplified gait cycle and three peak axial loading conditions were assessed (Normal, Overload and Overload Plus). Joints were lubricated with Ringer's solution and tests were conducted for 4 hours. Photographs were taken and compared to characterise cartilage surface and labral tissue pre, during and post simulation. The results showed no evidence of damage to samples tested under normal loading conditions, whereas the samples tested under overload and overload plus conditions exhibited different severities of tears and detachment of the labrum at the antero-superior region. The location and severity of damage was consistent for samples tested under the same conditions; supporting the use of this methodology to investigate further effects of altered loading and motion on natural tissue.
Topics: Acetabulum; Animals; Cartilage, Articular; Femur Head; Hip Joint; Swine; Weight-Bearing
PubMed: 35980907
DOI: 10.1371/journal.pone.0272264 -
BMJ Case Reports May 2021Gout is a common crystal-induced arthropathy affecting mainly the joints of the appendicular skeleton; however, rarely this condition affects the axial skeleton as well....
Gout is a common crystal-induced arthropathy affecting mainly the joints of the appendicular skeleton; however, rarely this condition affects the axial skeleton as well. Spinal gout can cause radiculopathy, cord compression, canal stenosis and discitis. We describe a case of a 71-year-old woman where the initial presentation of destructive arthropathy and spinal masses secondary to axial gout was mistaken for a metastatic malignancy. Despite chronic polyarthropathy and bilateral subcutaneous gouty tophi, spinal gout was not considered a differential diagnosis during initial assessment.The patient was managed conservatively with pharmacological treatment resulting in improvement of her upper limb radiculopathy and systemic joint pain, although little improvement in mobility. Such extensive involvement is rare and the masses can mimic an underlying metastatic disease. Careful history and clinical examination recognising polyarthropathy and subcutaneous tophi can aid the clinician to make the right diagnosis and institute correct treatment. Delay in recognising gout as a differential diagnosis can lead to marked morbidity as illustrated in our case.
Topics: Aged; Arthritis, Gouty; Female; Gout; Humans; Radiculopathy; Spinal Diseases; Spine
PubMed: 34059531
DOI: 10.1136/bcr-2020-236166 -
In Vivo (Athens, Greece) 2021Surgical treatment for spinal deformity aims to correct malformation, release the nerves, and reconstruct spinal stability. To explore and develop a new improved spinal...
BACKGROUND/AIM
Surgical treatment for spinal deformity aims to correct malformation, release the nerves, and reconstruct spinal stability. To explore and develop a new improved spinal correction system (ISCS) for clinical application, we studied the stability and biomechanical characteristics of the ISCS through finite element analysis and comparison of the ISCS with the pedicle screw and rod system (PSRS).
PATIENTS AND METHODS
Using L1-L3 CT image data of a normal adult male lumbar spine for establishment of L1-L3 finite element model, we established posterior internal fixation models for a comparative finite element analysis of PSRS and ISCS. An axial load of 500 N and a moment of 10 N•m were applied to L1 to simulate flexion, extension, lateral bending, and axial rotation. Stress distribution characteristics, load sharing, strain bending stiffness and strain angle change of the models were measured.
RESULTS
In flection and extension directions, the maximum stress of the L2 vertebral body and the L1/2 and L2/3 discs in PSRS was less than that of ISCS. In lateral bending and axial rotation directions, the maximum stress between PSRS and ISCS was similar. However, the stress shielding rate of L2, L1/2, and L2/3 intervertebral discs in ISCS was significantly lower than that of PSRS. We also found that both models had similar angular displacement and maximum displacement in lateral bending direction, but PSRS had a lower angular displacement and maximum displacement in flection and extension directions. Finally, we showed that PSRS had similar angular displacement and a lower maximum displacement compared with ISCS in axial rotation, whereas ISCS had lower bending stiffness than PSRS in different directions.
CONCLUSION
ISCS can effectively fix spinal deformities compared to PSRS. ISCS provides a new option for orthopedic surgery treatment of scoliosis and, therefore, warrants further clinical studies in patients with other spinal deformities.
Topics: Biomechanical Phenomena; Finite Element Analysis; Humans; Lumbar Vertebrae; Male; Pedicle Screws; Spinal Fusion
PubMed: 34182497
DOI: 10.21873/invivo.12491 -
Journal of Biomechanics May 2022Glenohumeral and scapulothoracic motion combine to generate humerothoracic motion, but their discrete contributions towards humerothoracic axial rotation have not been...
Glenohumeral and scapulothoracic motion combine to generate humerothoracic motion, but their discrete contributions towards humerothoracic axial rotation have not been investigated. Understanding their contributions to axial rotation is important to judge the effects of pathology, surgical intervention, and physiotherapy. Therefore, the purpose of this study was to investigate the kinematic coupling between glenohumeral and scapulothoracic motion and determine their relative contributions towards axial rotation. Twenty healthy subjects (10 M/10F, ages 22-66) were previously recorded using biplane fluoroscopy while performing arm elevation in the coronal, scapular, and sagittal planes, and external rotation in 0° and 90° of abduction. Glenohumeral and scapulothoracic contributions towards axial rotation were computed by integrating the projection of glenohumeral and scapulothoracic angular velocity onto the humeral longitudinal axis, and analyzed using one dimensional statistical parametric mapping and linear regression. During arm elevation, scapulothoracic motion supplied 13-20° (76-94%) of axial rotation, mainly via scapulothoracic upward rotation. The contribution of scapulothoracic motion towards axial rotation was strongly correlated with glenohumeral plane of elevation during arm elevation. During external rotation, scapulothoracic motion contributed 10° (8%) towards axial rotation in 0° of abduction and 15° (15%) in 90° of abduction. The contribution of scapulothoracic motion towards humerothoracic axial rotation could explain the simultaneous changes in glenohumeral plane of elevation and axial rotation associated with some pathologies and surgeries. Understanding how humerothoracic motion results from the functional coupling of scapulothoracic and glenohumeral motions may inform diagnostic and treatment strategies by targeting the source of movement impairments in clinical populations.
Topics: Adult; Aged; Biomechanical Phenomena; Humans; Humerus; Middle Aged; Range of Motion, Articular; Rotation; Scapula; Shoulder Joint; Young Adult
PubMed: 35367838
DOI: 10.1016/j.jbiomech.2022.111059 -
Anatomical Record (Hoboken, N.J. : 2007) Jul 2022Captive specimens in museum collections facilitate study of rare taxa, but the lifestyles, diets, and lifespans of captive animals differ from their wild counterparts....
Captive specimens in museum collections facilitate study of rare taxa, but the lifestyles, diets, and lifespans of captive animals differ from their wild counterparts. Trabecular bone architecture adapts to in vivo forces, and may reflect interspecific variation in ecology and behavior as well as intraspecific variation between captive and wild specimens. We compared trunk vertebrae bone microstructure in captive and wild xenarthran mammals to test the effects of ecology and captivity. We collected μCT scans of the last six presacral vertebrae in 13 fossorial, terrestrial, and suspensorial xenarthran species (body mass: 120 g to 35 kg). For each vertebra, we measured centrum length; bone volume fraction (BV.TV); trabecular number and mean thickness (Tb.Th); global compactness (GC); cross-sectional area; mean intercept length; star length distribution; and connectivity and connectivity density. Wild specimens have more robust trabeculae, but this varies with species, ecology, and pathology. Wild specimens of fossorial taxa (Dasypus) have more robust trabeculae than captives, but there is no clear difference in bone microstructure between wild and captive specimens of suspensorial taxa (Bradypus, Choloepus), suggesting that locomotor ecology influences the degree to which captivity affects bone microstructure. Captive Tamandua and Myrmecophaga have higher BV.TV, Tb.Th, and GC than their wild counterparts due to captivity-caused bone pathologies. Our results add to the understanding of variation in mammalian bone microstructure, suggest caution when including captive specimens in bone microstructure research, and indicate the need to better replicate the habitats, diets, and behavior of animals in captivity.
Topics: Animals; Bone Density; Bone and Bones; Mammals; Spine
PubMed: 34677912
DOI: 10.1002/ar.24817 -
Scientific Reports Nov 2022Stokes's equation in the fluid domain and Brinkman's equation in the porous media are combined in the current study which is designated by the Stokes-Brinkman coupling....
Stokes's equation in the fluid domain and Brinkman's equation in the porous media are combined in the current study which is designated by the Stokes-Brinkman coupling. The current paper gives a theoretical analysis of the Stokes-Brinkman coupling. It has been shown that such a model is a good match for the knee joint. A flow model has been investigated in order to get a better understanding of the convective diffusion of the viscous flow along the articular surfaces between the joints. The Beavers and Joseph slip conditions which are a specific boundary condition for the synovial fluid are used to solve the governing system of partial differential equations for the synovial fluid and the results are provided here. We develop formulas for the interfacial velocity for both flow through special slip condition and analyse the link between the slip parameters [Formula: see text] and [Formula: see text]. Thus, the damping force due to the porous medium naturally when we non-dimensionalize, some parameter which are controlling the structure like, [Formula: see text] and [Formula: see text]. Through the development of an analytical solution and numerical simulation (using the finite volume approach) it is hoped that the mechanisms of nutritional transport into the synovial joint will be better understood. According to the data the average concentration has a negative connection with both the axial distance and the duration spent in the experiment. Many graphs have been utilized to gain understanding into the problem's various characteristics including velocity and concentration, among others. Hyaluronate (HA) is considered to be present in porous cartilage surfaces and the viscosity of synovial fluid fluctuates in response to the amount of HA present.
Topics: Humans; Porosity; Viscosity; Computer Simulation; Knee Joint; Synovial Fluid
PubMed: 36348000
DOI: 10.1038/s41598-022-23402-7 -
Orthopaedics & Traumatology, Surgery &... Feb 2020Guided growth is part of the surgical armamentarium for limb-length discrepancy or axial deformity. It is an old concept, with several apparently conflicting techniques... (Review)
Review
Guided growth is part of the surgical armamentarium for limb-length discrepancy or axial deformity. It is an old concept, with several apparently conflicting techniques that are in fact usually complementary. Depending on whether the aim is to slow or arrest growth, to treat length discrepancy or axial deviation, techniques differ and the choice is partly determined by the indication. It is thus essential to know the technical details for each: temporary or definitive, complete or asymmetric, with or without implant. Considerations of fashion and personal habits may outweigh basic principles, and it is important to go back to the princeps descriptions: the Phemister, Bowen, Blount, Métaizeau and Stevens techniques and others all have their surgical specificities Apart from surgery itself, he indication and choice of technique depend on the patient's age and whether the abnormality to be treated is isolated or part of a wider syndrome, all of this being included in a precise strategy based on planning calculations that are indispensable ahead of any surgery. Guided growth can also be implemented elsewhere than in the limbs: wrist, ankle, or even hip; and it is beginning to be possible to correct sagittal and rotational deformities. All of this is furthermore achievable using emerging techniques that are less invasive, are reversible, and show equal efficacy.
Topics: Bone Lengthening; Child; Humans; Knee Joint; Radiography
PubMed: 31669550
DOI: 10.1016/j.otsr.2019.04.025 -
Cartilage Dec 2021There are limited data on bone dimension and cartilage thickness of the distal humeral articular surface. This study aimed to evaluate sex- and age-related bone...
OBJECTIVE
There are limited data on bone dimension and cartilage thickness of the distal humeral articular surface. This study aimed to evaluate sex- and age-related bone dimension and cartilage thickness differences and assess the effect of cartilage thickness on distal humeral shape.
DESIGN
Elbow magnetic resonance images of 180 healthy participants were evaluated. Cartilage thicknesses of the trochlea and capitellum were measured at 19 points using coronal and axial images. In addition, bone diameters were measured from the flexion-extension axis to the 19 points on the coronal and axial magnetic resonance images. Sex differences were evaluated, and the correlation between age and measurement parameters was assessed.
RESULTS
Significant sex differences regarding the diameters of the axial trochlear bone, coronal lateral trochlear bone, and medial capitellar bone, cartilage thickness at the apex of the lateral trochlear ridge in the axial and coronal plane and at the most lateral point of the capitellar articular surface in the axial plane were observed. A negative correlation was observed between age and axial plane trochlear bone dimensions and between age and coronal plane lateral trochlear and medial capitellar bone dimensions. No significant correlation was found between cartilage thickness and bone dimensions.
CONCLUSIONS
Bone dimension and cartilage thickness at the distal humerus vary according to sex and age. The data could be used in the donor site selection and graft preparation while osteochondral autograft transfer and allograft transplantation, and in the development of gender-compatible hemiarthroplasty implants.
Topics: Cartilage; Elbow Joint; Female; Humans; Humerus; Magnetic Resonance Imaging; Male; Sex Characteristics
PubMed: 32037860
DOI: 10.1177/1947603520903780